281 research outputs found

    Multi-ingredient pre-workout supplements, safety implications, and performance outcomes: a brief review

    Get PDF
    In recent years, a new class of dietary supplements called multi-ingredient pre-workout supplements (MIPS) has increased in popularity. These supplements are intended to be taken prior to exercise and typically contain a blend of ingredients such as caffeine, creatine, beta-alanine, amino acids, and nitric oxide agents, the combination of which may elicit a synergistic effect on acute exercise performance and subsequent training adaptations compared to single ingredients alone. Therefore, the purpose of this article was to review the theoretical rationale and available scientific evidence assessing the potential ergogenic value of acute and chronic ingestion of MIPS, to address potential safety concerns surrounding MIPS supplementation, and to highlight potential areas for future research. Though direct comparisons between formulations of MIPS or between a MIPS and a single ingredient are challenging and often impossible due to the widespread use of “proprietary blends” that do not disclose specific amounts of ingredients in a given formulation, a substantial body of evidence suggests that the acute pre-exercise consumption of MIPS may positively influence muscular endurance and subjective mood, though mixed results have been reported regarding the acute effect of MIPS on force and power production. The chronic consumption of MIPS in conjunction with a periodized resistance training program appears to augment beneficial changes in body composition through increased lean mass accretion. However, the impact of long-term MIPS supplementation on force production, muscular endurance, aerobic performance, and subjective measures is less clear. MIPS ingestion appears to be relatively safe, though most studies that have assessed the safety of MIPS are relatively short (less than eight weeks) and thus more information is needed regarding the safety of long-term supplementation. As with any dietary supplement, the use of MIPS carries implications for the athlete, as many formulations may intentionally contain banned substances as ingredients or unintentionally as contaminants. We suggest that athletes thoroughly investigate the ingredients present in a given MIPS prior to consumption. In conclusion, it appears that multi-ingredient pre-workout supplements have promise as an ergogenic aid for active individuals, though further information is required regarding long-term efficacy and safety in a wider variety of populations

    Compartmentalization of Cells Bearing "Rheumatic” Cell Surface Antigens in Peripheral Blood and Tonsils in Rheumatic Heart Disease

    Get PDF
    Monoclonal antibodies that recognize "rheumatic” antigens of peripheral blood non-T cells were used to study the compartmentalization of such cells in peripheral blood and tonsils of individuals with rheumatic heart disease (RHD) and suitable control subjects. The peripheral blood of most (71%) of the 42 individuals with RHD contained cells reacting with monoclonal antibody 83S19.23 or 256S.10, whereas these cells were present in only 17% of the 41 control subjects (P < .02). However, none of 21 individuals with RHD had such cells in their tonsils, although they were present in the tonsils of 50% of the 40 control subjects (P < .03). These results may reflect a failure in RHD of organ-specific homing of cells with the epitopes recognized by the antibodies. The presence of these cells in tonsils may be important in the immune response to streptococcal pharyngeal infection, and their absence in RHD may be involved in the unusual immune responses characteristic of this diseas

    Cytosolic NADPH balancing in Penicillium chrysogenum cultivated on mixtures of glucose and ethanol

    Get PDF
    The in vivo flux through the oxidative branch of the pentose phosphate pathway (oxPPP) in Penicillium chrysogenum was determined during growth in glucose/ethanol carbon-limited chemostat cultures, at the same growth rate. Non-stationary 13C flux analysis was used to measure the oxPPP flux. A nearly constant oxPPP flux was found for all glucose/ethanol ratios studied. This indicates that the cytosolic NADPH supply is independent of the amount of assimilated ethanol. The cofactor assignment in the model of van Gulik et al. (Biotechnol Bioeng 68(6):602–618, 2000) was supported using the published genome annotation of P. chrysogenum. Metabolic flux analysis showed that NADPH requirements in the cytosol remain nearly the same in these experiments due to constant biomass growth. Based on the cytosolic NADPH balance, it is known that the cytosolic aldehyde dehydrogenase in P. chrysogenum is NAD +  dependent. Metabolic modeling shows that changing the NAD + -aldehyde dehydrogenase to NADP + -aldehyde dehydrogenase can increase the penicillin yield on substrate
    • …
    corecore